Enable detection of failed encryption process, for bug 3384231.

Need to detect if the encryption process didn't finish successfully, and if
so, provide a way for the UI to detect that and give the user an option to
wipe the system clean.  Otherwise, the user is stuck in a reboot loop, and
they will need to do magic button presses to enter recovery and wipe the
device to get out of it.

Change-Id: I58253e1e523ee42bdd1a59aa7d8a9d20071bd18b
1 file changed